JP2003222510A - Imaging method of wiring pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging method of a wiring pattern capable of acquiring a clear image by removing influence of a bedding internal layer wiring pattern when imaging the outermost-layer wiring pattern of a high-density semiconductor packaging multilayer interconnection board. <P>SOLUTION: An object tape 1 comprising a semiconductor packaging multilayer interconnection board is positioned and fixed by a work fixing mechanism 7, and the outermost-layer wiring pattern of the object tape 1 is imaged by an imaging means comprising a sensor 2, an imaging lens 3, a filter 4 and an illumination 5. In this case, this method is characterized by imaging the outermost-layer wiring pattern of the semiconductor packaging multilayer interconnection board by using the illumination 5 having a wave range below 450 nm which is a low wave range of a transmission spectral sensitivity characteristic and a reflection spectral sensitivity characteristic of an insulating base material comprising a polyimide film or a polyimide resin and an insulating layer, or by using a band-pass filter 4. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for picking up an outermost wiring pattern of a multilayer wiring board for a semiconductor package in which a wiring pattern and an insulating layer are sequentially formed on both sides of an insulating base material.

[0002]

2. Description of the Related Art In general, a multilayer wiring board (also called a carrier tape) for a semiconductor package, which is generally used for the purpose of reducing the size and weight of electronic equipment, has a polyimide film as an insulating base material and a copper foil laminated with an adhesive or the like. To form a conductor layer, patterning the conductor layer to form a first wiring pattern, further forming an insulating layer made of a polyimide resin, and forming a wiring pattern by a subtractive method or a semi-additive method. The desired multilayer wiring board for a semiconductor package is formed by repeating the process. Here, in the multilayer wiring board for a high-density semiconductor package, the thickness of the degree wiring pattern is 5 to 10 μm, and the width of the wiring pattern is about 10 μm in the portion having the highest degree of integration.

During the manufacturing process of this multilayer wiring board for a semiconductor package, the wiring pattern is thinned (broken), broken,
Heavy defects such as shorts and fat (protrusions) occur. Therefore, conventionally, the presence or absence of these defects has been discriminated by a continuity inspection or a visual inspection. However, the visual inspection has problems such as a finer pattern, skill required, inspection standard variations due to the physical condition of the inspector, problems of inspection personnel, and correspondence to increase in production quantity. Therefore, recently, various automatic inspection apparatuses have been proposed which automatically inspect the presence or absence of defects by using a camera. Further, in the above-mentioned multilayer wiring board for semiconductor package, it is almost impossible to visually inspect various defects existing on a wiring pattern having a minimum width of 10 μm, and automatic inspection is indispensable.

In general, an automatic inspection apparatus for automatically inspecting for defects using a camera uses a plurality of cameras (line sensors, area sensors, etc.) to form a plurality of wiring patterns on a multilayer wiring board for the same semiconductor package. At the same time, images are picked up by time difference, area division, etc., and the images are subjected to recognition processing to detect defects such as thinning, disconnection, short-circuiting, and thickening existing in the pattern. In the recognition processing, CAD data or a non-defective sample is taken in as a master image, and the difference between the master image and the inspection image (inspection target pattern image) is determined as a defect. The inspection image at this time was displayed by paying attention to the pattern formed on the outermost layer of the semiconductor package multilayer wiring board, and most of the images are taken without considering the influence of the underlying wiring pattern. is there. The reason for this is that the product does not have the underlying wiring pattern, and even if the product has the underlying wiring pattern, the type of insulating base material or insulating layer interposed between the wiring patterns and the insulating base material, the insulating base material The thickness of the outermost layer does not affect the imaging of the outermost layer pattern, and even if there is an underlying wiring pattern and it has some effect, it can be easily eliminated by adjusting the threshold value during imaging. Therefore, it is not necessary to consider the influence of the reflection of the underlying wiring pattern as an optical problem.

However, in the above-mentioned multilayer wiring board for a high-density semiconductor package, the thickness of the insulating layer made of a polyimide film or the like interposed between the wiring patterns is 10 to 10.
The thickness is as thin as about 25 μm, and when an attempt is made to image the outermost layer pattern, the inner layer wiring pattern existing in the base is reflected, and there is a problem that a clear wiring pattern image focusing only on the outermost layer wiring pattern cannot be obtained. .

Further, in order to capture the wiring pattern as a picked-up image by a camera and inspect using the picked-up image, the illumination condition is also important, and even if the processing algorithm is sophisticated if a defect cannot be revealed by the illumination. A reliable test is impossible. Therefore, it is necessary to set appropriate illumination conditions for each inspection.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and eliminates the influence of the underlying inner layer wiring pattern when imaging the wiring pattern of the outermost layer of a multilayer wiring board for high density semiconductor packages. An object of the present invention is to provide a method for imaging a wiring pattern that can obtain a clear and clear image.

[0008]

In order to solve the above problems in the present invention, in a first aspect of the present invention, there is provided a multilayer wiring board for a semiconductor package in which a wiring pattern and an insulating layer are sequentially formed on both surfaces of an insulating base material. A method for picking up an image of the wiring pattern of the outermost layer, wherein the wiring pattern of the outermost layer of the multilayer wiring board for a semiconductor package is imaged by illumination having a wavelength range of 450 nm or less, or an image pickup means using a bandpass filter. This is an image pickup method for a wiring pattern.

According to a second aspect of the present invention, in the image pickup method according to the first aspect, the wiring pattern of the outermost layer of the multilayer wiring board for a semiconductor package is imaged by the image pickup means using high-angle reflective illumination. This is a method for imaging a wiring pattern.

Furthermore, in claim 3, the insulating base material and the insulating layer are made of a polyimide film or a polyimide resin.
The method for imaging the wiring pattern described in (1) is used.

The wiring pattern imaging method of the present invention uses a polyimide film or a polyimide resin as an insulating base material and an insulating layer of a multilayer wiring board for a semiconductor package, and a transmission spectral sensitivity characteristic and a reflection spectral sensitivity characteristic of the polyimide film or the polyimide resin. Is a low wavelength region of 45
It has been found that an image of the outermost layer wiring pattern having a high definition can be obtained by imaging the outermost layer pattern by using an illumination device having a wavelength range of 0 nm or less, or an imaging means having a bandpass filter and a high-angle reflective illumination. It was

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 conceptually shows an embodiment of the present invention. The target tape 1 made of a multilayer wiring board for a semiconductor package is fixed in position by a work fixing mechanism 7. As the work fixing method at this time, it is possible to establish work flatness within the depth of focus of the image pickup optical system by performing glass sandwich or vacuum adsorption with transparent optical glass with an antireflection film on the surface, and against work warpage. However, a fixing method that can be corrected is desirable. Further, if the work has a reel shape, it is possible to add a transport tape runner mechanism to both sides of the work fixing mechanism 7.

The sensor 2, the imaging lens 3, the filter 4 and the illumination 5 are selected and constructed in accordance with a wavelength range of 450 nm or less, which is a wavelength range in which the transmission spectral sensitivity of the polyimide film or the polyimide resin is low. As for the sensor 2 and the imaging lens 3, the wiring pattern of the target tape 1 is at least 10 μm.
Since it is fine, an optical design is used so that the image obtained by imaging has high resolution. The resolution at that time is preferably about 1 μm and 2 μm so that the pattern edge information can be obtained sufficiently sufficiently, but the target of this resolution setting is about 1/9 to 1/10 of the target pattern width.

The illumination 5 uses high-intensity illumination that emits light over the entire visible range, and the filter 4 cuts a wavelength range of 450 nm or more from the spectral reflection sensitivity characteristics and spectral transmission sensitivity characteristics of the polyimide film or polyimide resin. Use a bandpass filter. Alternatively, a light source that emits light only in a required wavelength range is used due to the spectral sensitivity of the polyimide film or the polyimide resin. If necessary in order to obtain a plurality of pattern images existing on the same tape, a mechanism for moving the image pickup section composed of the sensor 2, the imaging lens 3, the filter 4 and the like, and the work fixing mechanism in the necessary take-in direction is also included.

The sensor 2 is connected to an arithmetic unit 6 composed of a personal computer, a keyboard, a mouse, a display, etc., and the image formed here is reconstructed as a pattern image to perform various arithmetic operations and recognition processing. It is also responsible for the work fixing mechanism and user interface.

[0016]

EXAMPLE FIG. 2 shows spectral transmittance characteristics and spectral reflectance characteristics data of a polyimide film and a polyimide resin used for an insulating base material and an insulating layer of a multilayer wiring board for a semiconductor package, and FIG. 3 is used for forming a wiring pattern. The spectral reflectance characteristic data of the copper foil are shown below. Utilize the wavelength range that avoids the light absorption effect of the base material contained in the polyimide film and copper foil by obtaining the base material spectral sensitivity information for forming such an insulating base material, insulating layer and wiring pattern in advance. To obtain a clear pattern image.

RGB illumination is used as the illumination 5, and an example of an image of the wiring pattern depending on the illumination conditions is shown in FIGS. 4 and 5. R component (near 650 nm), G component (520
Next, an image capturing comparative example will be shown for the case where RGB illumination that emits wavelength ranges of B component (around 450 nm) and B component (around 450 nm) are used, and the case where all wavelengths of B component (around 450 nm) are turned on. Figure 4 when all RGB are turned on
As shown in FIG. 5, the inner layer wiring pattern can be confirmed in addition to the outermost layer wiring pattern, whereas when the B component near 450 nm is turned on, only the outermost layer wiring pattern is clearly visible as shown in FIG. In this way, a clear pattern image can be obtained by utilizing the wavelength range avoiding the influence of light absorption by the base material.

Next, FIGS. 6 and 7 show examples of image pickup of the wiring pattern of the multilayer wiring board for semiconductor package depending on the difference in the illumination angle between the side illumination (tapered illumination) and the high angle illumination. In the side illumination, the inner layer wiring pattern can be confirmed in addition to the outermost layer wiring pattern as shown in FIG. 6, whereas in the high-angle illumination, only the outermost layer wiring pattern is clearly visible as shown in FIG. . Generally, in the case of only coaxial (high angle) illumination, only the top surface of the wiring pattern is brightly projected, and protrusions and space defects due to etching defects cannot be revealed. However, by applying lateral illumination thereto, the protrusion can be made bright and visible due to slight etching residue. By utilizing an illumination system that combines the advantages of high-angle illumination and side illumination in this way, it is possible to obtain a clear pattern image that is not affected by the underlying pattern.

[0019]

As described above, according to the wiring pattern imaging method of the present invention, by using the polyimide film or the polyimide resin as the insulating base material and the insulating layer of the multilayer wiring board for the semiconductor package, the inner layer wiring pattern can be formed. Only the uppermost layer wiring pattern can be picked up as a clear image without being affected, and it can be provided as an effective image used for automatic inspection of the wiring pattern of the semiconductor package multilayer wiring board.

[Brief description of drawings]

FIG. 1 is an explanatory view conceptually showing an embodiment of a wiring pattern of the present invention.

FIG. 2 is a graph showing spectral transmittance characteristics and spectral reflectance characteristics of a polyimide film or a polyimide resin used for an insulating base material and an insulating layer.

FIG. 3 is a graph showing a spectral reflectance characteristic of a copper foil used for forming a wiring pattern.

FIG. 4 is an image example of a wiring pattern imaged by using RGB illumination as illumination.

FIG. 5 is an image example of a wiring pattern imaged using B illumination (around 450 nm) as illumination.

FIG. 6 is an image example of a wiring pattern imaged by using side illumination (tapered illumination) as illumination.

FIG. 7 is an image example of a wiring pattern imaged by using high-angle illumination as illumination.

[Explanation of symbols]

1 ... Target tape 2 ... Sensor 3 ... Imaging lens 4 ... Filter 5 ... Lighting 6 ... Calculator 7: Work fixing mechanism

Claims (3)

[Claims] 1. A method for picking up an image of a wiring pattern of an outermost layer of a multilayer wiring board for a semiconductor package in which a wiring pattern and an insulating layer are sequentially formed on both surfaces of an insulating base material.
An image pickup method for a wiring pattern, characterized by picking up an image of the wiring pattern of the outermost layer of a semiconductor package multilayer wiring board by an image pickup means using an illumination having a wavelength range of 450 nm or less or a bandpass filter. 2. The image pickup method according to claim 1, wherein an image pickup means using high-angle reflective illumination picks up an image of the outermost wiring pattern of the multilayer wiring board for a semiconductor package. 3. The wiring pattern imaging method according to claim 1, wherein the insulating base material and the insulating layer are made of a polyimide film or a polyimide resin.